"This will be a day long remembered. It has seen the end of Kenobi, it will soon see the end of the Rebellion."Vader kills Obi Wan at the wreckage of Alderaan, then the Death Star goes through hyperspace to Yavin. My chart says that trip would about 20 hours with a x4 hyperdrive, so we're just on the edge of calling Vader's quote literally true. This also allows the Rebellion something like 17.5 hours to study the stolen Death Star plans to find the thermal exhaust port weakness.
Another key component is the travel time from Tatooine to Alderaan, which isn't explicitly stated in the movie, but certainly seems like a few hours (not a day or more). The chart says the Falcon could make that trip in about 4 hours.
Sadly, the chart I have made disagrees completely with at least three bits of Star Wars conventional wisdom: for one thing it is said that it would take weeks to cross the galaxy (re-stated in the Edge of the Empire RPG main rulebook), for another it is said that somehow the density of mass shadows affects travel times (even though in a standard spiral galaxy the numeric density of stars near the core would be literally hundreds of times higher than out on the rim...but nobody suggests travel times in the core should take hundreds of times longer!), and finally they seem to suggest that the known hyperspace trade routes are somehow safer, preferred, and possibly required travel paths. I can get behind the notion that BoSS collects (anonymous?) route data for all ships landing at heavily populated worlds, then uses these calculations to produce up to date "fresh" maps for people. But I don't think the trade corridors are anything more special than just that: heavily traveled trade routes connecting a ton of planets that like to trade with one another.
As for any calculations related to subspace speeds and whatnot, I cannot muster up enough energy to wish to work on that. I think using the shorthand method of "minutes required to reach a hyperspace jump point", etc, is good enough.
Next up is to begin the process for naming all the NPCs involved thus far, both Tierfon personnel and the Sumitra Sector Imperials who most directly oppose them. After that, the goal will be to write the first X-wing Miniatures Game mission, the first Age of Rebellion adventure, and the first Tierfon Tales short story. Sounds fun!